Abstract
In the following work a correlation was inferred of the effects of material behaviour in different zones of the extruder screw channel with a number of process parameters. Calculus of the average temperature variation of the processed material with length and depth of the screw channel allows effective positioning of intense mixing zones, resulting in enhanced melt thermal homogeneity and product quality. Relationships for the flow-rate of the feeding zone, the specific power and the efficiency of the extrusion process allow the overall performance calculus of the extruder. To increase process efficiency one must reduce the heat loss, Ql which results in energy savings and the decrease of thermal pollution of the environment. It becomes thus possible to replace a certain number z of actual extruders with diameter D, each with a total installed power Nt,1 and flow-rate Gm,1, with a single extruder of the same diameter D assuring a flow-rate Gm = z . Gm,1 and whose total installed power is Nt [ z . Nt,1. Heat lost through the external surface of the heating system of z extruders (z . Q1,l) is higher than that of a single modern extruder. Consequently, process efficiency in the up-graded extruder is higher than that of the extruders, resulting in diminished energy related expenses and cost of the mass unit of extruded product along with less environment pollution. Keywords: extrusion process; extruder performance; output; extruder efficiency; thermal pollution; energy